Understanding
MIDI
Interfaces

The Role of the MIDI Interface, with Real World Examples

Tweak's MIDI system as seen by Mac OSX.
Note how the system "sees" the MIDI ports on my Unitor 8 system, 828mk2, Remote
SL. All of those ins and outs are simultaneously active and ready for use
in my sequencers.

Building
a MIDI riginside your computer-based
recording studio? Then you know you need a MIDI interface of some sort. The
more midi devices you have the more a separate MIDI interface is necessary.
Sure, you can start off with using the typically single port on your audio
interface. Maybe you can get away with that and the USB midi interface built
into your keyboard controller. Maybe not. Lets take a look.

Do I even need a MIDI interface?

Note that if you are exclusively dealing with software
synths you don't need an dedicated MIDI interface. A single MIDI port will do fine,
as all you have to do is connect a keyboard controller. On some controllers with
USB outputs, this interface is built-in). Inside the software you are using, the
softsynth will build it's own virtual midi channels as needed. It's when you
are using hardware MIDI devices that a MIDI interface is needed. The
more gear you have the more ports you need. So you decide how much MIDI gear
you think you will get? There is a lot of different gear that uses MIDI.
Its not just keyboards. MIDI sound modules require MIDI
connections. Effect processors, such as reverbs, delays, harmonizers,
guitar pedal rigs, use MIDI to dump data and switch programs. Multi-track recorders
use MIDI for MIDI Time Code and MIDI Machine Code.
Control Surfaces usually require a whole 16 channels in and out in order
to send and receive data from your sequencer. You can find 1x1, 2x2, 4x4 and 8x8 MIDI interfaces
commonly available. How many ports do you need? Read on.

MIDI
Interfaces at zZounds

Mark of the Unicorn (MOTU) FastLane USB MIDI InterfaceThe professional MIDI interface for your home studio:
FastLane is a simple 2 input, 2 output, 32-MIDI channel interface for
Macintosh and Windows. It installs in seconds and opens your computer to
a world of music software. FastLane's unique advantage: a MIDI thru
button allows you to play to your gear even when your computer is turned
off - without having to disconnect cables. No other USB interface offers
this feature for this price.

M-Audio Midisport 2x2 Anniversary Edition USB Midi IntefaceThe Midisport 2x2 was first introduced in 2000--and
quickly became the world's most popular USB MIDI interface. This
overwhelming success inspired the creation of an entire Midisport line
designed to meet the varying needs of diverse music makers. M-Audio's
special Anniversary-edition Midisport products commemorate this success
with a brand-new look. Priced from 69.00

Mark
of the Unicorn (MOTU) MIDI Express 128 8x8 Bus Powered InterfaceBuilt from the same technology found in MOTU's flagship
MIDI Timepiece, the MIDI Express 128 is a professional MIDI interface
that provides plug-andplay connectivity to any USB-equipped Macintosh or
Windows computer. The Express 128 provides 8 MIDI IN, 9 MIDI OUT, 128
MIDI channels and compatibility with all Macintosh and Windows software.

Why get a dedicated MIDI Interface?

"Whoa dude" you might think, that you will never
need 128 MIDI channels. But it is rather surprising when one gets into MIDI
gear how quickly these channels get used up. Want a Mackie Control (or automated
digital mixer or control surface)? Count off 16 channels used. A multitimbral
keyboard/master controller? 16 more used; 32 gone now. A emu proteus
2000 module (which has 2 MIDI in ports)? There goes another 32, only 64 left.
Hardware sampler? 48 left. Say you bought some vintage stuff on ebay, maybe
a Juno, a TX802, you are now down to 16. Hook up a few FX boxes and you only
have a few channels left.

To be sure, you can be as stingy as you want with
MIDI channels if you take the time to configure your synth to only respond to a
few channels for each piece. For example I can turn off 30 channels on my
Proteus 2000 and only use 2 if I want, and I could chain up 16 modules to a single
midi port if I wanted to. But I don't want to. I want the freedom to use
all 16 channels of my triton in every song and all 32 of my proteus 2000.
Why? When you are making a song its easier not to use program change commands.
You just set the channel to a program and it stays there. You can use a whole
channel just for one little hit inside a song. Building up a string section
on a module might take 5 or 6 MIDI channels and programs. Creating a drum track
might mean using one channel for each drum instead of using a preset one channel
kit. So why do we get a large MIDI interface? Call it compositional
freedom if you will.

MIDI is old tech. Even when it was introduced
in 1983, people where already complaining that the bandwidth of the MIDI port was
too small; that it could not effectively handle a full 16 channels of notes. The
solution was to add more ports, so one could "spread out the load" to different
ports and different modules.

I have both a Unitor8 and an AMT8. They can
be ganged together with a single cable, turning the 8x8 into a 16x16. You
can gang up to 8 of these MIDI interfaces together. Ok I can't resist. 128x8
channels is 1,024 MIDI channels. Enough? It better be, cause
you can't do more than this without adding more computers. I've had
my interfaces over 3 years and they work really well. I've used them on PCs,
a Mac G5 and a G4 powerbook, and I've used them connected to the serial port and
the USB port. Both methods are fast and reliable.

But not everyone
needs that kind of power. So how many ports/channels do you need? Kind of depends
on your style. If you don't mind daisy chaining midi devices and turning channels
off on your multi-timbral devices, a simple
m-audio
MIDIsport 2x2 will do just fine for most people. That would give you 32 channels on 2 ports. That means only 2
devices can go into the computer, but as many as 32 could go out, given that each
device only has 1 channel. Of course, all multitimbral synths have many channels
so that might not make sense for you.

You can daisy chain
up to 16 devices going out of a single port of the midi interface, but that is not true going
in to the MIDI interface. There is no way to daisy chain to a MIDI input on a midi
interface. You need a whole port for any device that goes in to
the computer

Tweak: The MIDISport 2x2 MIDI
interface is a very popular USB solution

Real World MIDI
configurations

Remember every MIDI
port (one midi in connector and one midi out connector on an interface)
carries 16 channels of data. However, you physically can connect only 1 device to
a midi input. (The only exception here is if you have a MIDI merge box that will
combine several midi cables to one midi stream).

To connect multiple
devices to a MIDI OUT port you connect the MIDI THRU on the 1st device to the MIDI
IN on the second device. The second device's MIDI THRU goes to the MIDI IN of the
third device, and so on. Do not confuse midi ports with the jacks on your keyboard--those
are not ports. Ports are on the midi interface as they connect directly
to the computer usually through USB. So you got that? The MIDI interface connects
the keyboard to and from the computer. Exception: Note that some controllers have
USB ports that connect directly to the computer. Those may be considered as a built
in 1x1 MIDI interface.

Understanding this
is hard at first. So I will give you several examples:

MIDI Helper devices (not to be confused with
MIDI Interfaces)

As you
note from above I talk about MIDI merge boxes. These merge 2 (or
more) MIDI outs of midi devices to one single MIDI out so they can share a
single port. Mergers come in handy, as many of us with multiple
controllers tend to run out of inputs to the computer. Synth
programmers too like them because every synth needs a midi out when you
get SysEx.

For example you could connect your keyboard and MPD16
to a merger and they would both control the track you are working on.

Or you could have 4 synth modules connected to a 4:1
merger and get system exclusive code from each without swapping cables
when programming.

MIDI Solutions Quadra Merger ProcessorThe MIDI Solutions Quadra Merge packs 4 MIDI inputs into
a 4.5 in. x 2.5 in. x 1.25 in. package. All MIDI messages appearing at
the 4 inputs of the Quadra Merge are merged to the output. All MIDI data
types are merged, including System Exclusive and MIDI Time Code. A fast
merging algorithm ensures that the MIDI data is processed with minimal
delay.

We also have what may be called MIDI splitter
boxes (or thru boxes) These connect to the output of a midi interface and allow you
to connect to several midi devices to it. However, they don't give you
more ports. They work exactly the same as using the MIDI THRUS on your
midi devices. You still have to turn off channels on your synths as
everything connected to the splitter will share the same midi port.

These boxes are helpful when you have a lot of devices
with a midi in and out but no Thru and you don't want to get another
MIDI interface. Many people think they get extra channels with
these devices but let me assure you--you don't!

MIDI Solutions Quadra Thru ProcessorThe MIDI Solutions Quadra Thru is a 1-in 4-out MIDI Thru
Box. All MIDI messages appearing at the input are sent to all 4 Thru
outputs. Active circuitry cleans up any skewing of MIDI data bits that
has occurred at the input, insuring reliable operation in setups that
require daisy chaining or long cable runs.

MIDI Patch bays: These may have several
inputs and outputs. A common configuration is the 3X8. These also do not
give you more MIDI ports, just a convenient way to route from the ports
you already have on your MIDI interface. Keep in mind that all of these
devices only extend the MIDI ports you already have on your midi
interface, they are not a substitute for a midi interface.

5 common MIDI Hookup examples

Example 1:

Lets say you had a Triton (16ch) , an electribe EA (2 ch), 3 midi FX boxes (1ch
ea) and a Mackie Control (16 channels). Which interface do you need? Can you figure
it out?

In this situation
you need at minimum a 3x3 midi interface. First lets go TO the interface: Triton
goes to MIDI IN 1, Mackie goes to MIDI IN 2 and the Electribe goes to MIDI IN 3.
The FX boxes do not need to send data to the computer to work.

Now, lets go OUT
of the MIDI interface. Out 1 goes to the Triton; Out two goes to the Mackie; Out
3 goes to the FX box 1; the THRU on FX box 1 goes to the IN of FX box 2; the THRU
of FX Box 2 goes to the IN of FX box 3; the THRU of FX box 3 goes to the Electribe.

Of course you won't
find many 3x3 interfaces so go for a 4x4.

Example 2:

You have a USB controller keyboard and will be running only soft synths. Do you
need an interface? Answer: No.

Example 3:

You have an audio interface
with 4 midi ins and outs. Do you need an interface?
Answer: No. The MIDI ins and outs connect directly to the computer (through Firewire
typically) and you don't need anything else, unless you get more than 4 controllers.

Example 4:

You are a synth collector and have 16 synths and modules. You want all of them to
send and receive because you are working a lot with patches with sysex data. What
is the minimum you can get by with? If you use only 1 channel on each you can get
by with a 1x1 and a 16ch midi merge box, if you can find one. Ideally you would
get 2 8x8's to make this a simpler operation. That way each synth has its own in
and out, with no changing and merging. Or you could get one 8x8 and use an 8 ch
merge box.

Example 5:

You have one keyboard and 4 modules and have a 1x1 midi interface on your soundcard
built in. How to hook this up?

I would put the keyboard
and your 3 best modules on a 4x4 MIDI interface and use the soundcard midi interface
for your least used module

Example 6:

You only have a 1x1 interface on the soundcard but have 2 controllers. How to get
them both in to the computer simultaneously? You get a 2-to-1 MIDI merge box or
break down and get a 2x2 midi interface (recommended).

Ok, its time for Questions and Answers

Questions from
the audience:

Q) Is USB OK for
MIDI interfaces? I heard it was bad.

A) USB is fine for
MIDI. Its Audio that is troublesome with USB sometimes due to the narrow bandwidth
of the USB 1.1 spec. However, midi data is very small and efficient code compared
to audio and a single USB cable can handle up to eight 8x8 midi interfaces if the
manufacturer allows such connection.

Q) Is there a such thing as a high
quality MIDI cable? Will it make me sound better?

A) MIDI cables only have a negative effect on sound when they
break. And that happens rarely, and only to the absolute cheapest garbage
cables. Do you know that my MIDI cables have lasted longer than any piece
of equipment I own? Its true! The main thing is to have enough
cables for your gear, ideally at the proper lengths. But don't worry, they
still work if too long.

Q) How Long can they Be?

A) 50 feet

Q) What is SysEx?

A) SysEx is short for System Exclusive Code, which is MIDI
data that is designed to control specific models of gear. Synth patches
are usually in the form a SysEx and they can be shuttled to and from a computer
for editing in synth editor applications.

I hope this has helped
you understand how the MIDI interface fits into the scheme of your computer-based
rig. It can be tricky to understand at first so if you have questions come over
the studio-central configuring
your rig forum and ask. We have the answers.

Cool Quote:

"The soul of music slumbers in the shell
Till waked and kindled by the master’s spell;
And feeling hearts, touch them but rightly, pour
A thousand melodies unheard before!"